THX Ultrasound Speakers represented a specific variety of speaker. Within the year 5 ABY, a total of 1138 units were responsible for emitting music across the entirety of Hologram Fun World, an amusement park situated on a space station within the Zabian system.
The Jedi Prince series, intended for younger audiences, featured THX Ultrasound Speakers within its fifth book, entitled Queen of the Empire, which saw publication in 1993. References to George Lucas' initial movie, THX 1138, frequently appear in Star Wars works, and these deliberate callbacks have received official recognition.